diff --git a/build/openresty/patches/nginx-1.25.3_07-fix-lua-context-clean-by-send-header.patch b/build/openresty/patches/nginx-1.25.3_07-fix-lua-context-clean-by-send-header.patch
new file mode 100644
index 000000000000..4db81ee59cbf
--- /dev/null
+++ b/build/openresty/patches/nginx-1.25.3_07-fix-lua-context-clean-by-send-header.patch
@@ -0,0 +1,45 @@
+diff --git a/bundle/ngx_lua-0.10.26/src/ngx_http_lua_util.c b/bundle/ngx_lua-0.10.26/src/ngx_http_lua_util.c
+index 8fd2656..b2fdb6c 100644
+--- a/bundle/ngx_lua-0.10.26/src/ngx_http_lua_util.c
++++ b/bundle/ngx_lua-0.10.26/src/ngx_http_lua_util.c
+@@ -549,6 +549,10 @@ ngx_http_lua_send_header_if_needed(ngx_http_request_t *r,
+         if (!ctx->buffering) {
+             dd("sending headers");
+             rc = ngx_http_send_header(r);
++            if (r->filter_finalize) {
++                ngx_http_set_ctx(r, ctx, ngx_http_lua_module);
++            }
++
+             ctx->header_sent = 1;
+             return rc;
+         }
+diff --git a/bundle/ngx_lua-0.10.26/t/002-content.t b/bundle/ngx_lua-0.10.26/t/002-content.t
+index 54de40e..eb9d587 100644
+--- a/bundle/ngx_lua-0.10.26/t/002-content.t
++++ b/bundle/ngx_lua-0.10.26/t/002-content.t
+@@ -1098,3 +1098,25 @@ failed to load inlined Lua code: content_by_lua(...45678901234567890123456789012
+ GET /lua
+ --- response_body_like: 503 Service Temporarily Unavailable
+ --- error_code: 503
++
++
++
++=== TEST 52: send_header trigger filter finalize does not clear the ctx
++--- config
++    location /lua {
++        content_by_lua_block {
++            ngx.header["Last-Modified"] = ngx.http_time(ngx.time())
++            ngx.send_headers()
++            local phase = ngx.get_phase()
++        }
++        header_filter_by_lua_block {
++            ngx.header["X-Hello-World"] = "Hello World"
++        }
++    }
++--- request
++GET /lua
++--- more_headers
++If-Unmodified-Since: Wed, 01 Jan 2020 07:28:00 GMT
++--- error_code: 412
++--- no_error_log
++unknown phase: 0
diff --git a/changelog/unreleased/kong/fix-filter-finalize-in-send-header-clear-context.yml b/changelog/unreleased/kong/fix-filter-finalize-in-send-header-clear-context.yml
new file mode 100644
index 000000000000..cac4566c7b4c
--- /dev/null
+++ b/changelog/unreleased/kong/fix-filter-finalize-in-send-header-clear-context.yml
@@ -0,0 +1,3 @@
+message: Fixed an issue where `lua-nginx-module` context was cleared when `ngx.send_header()` triggered `filter_finalize` [openresty/lua-nginx-module#2323](https://github.com/openresty/lua-nginx-module/pull/2323).
+type: bugfix
+scope: Core
\ No newline at end of file
diff --git a/spec/02-integration/05-proxy/24-buffered_spec.lua b/spec/02-integration/05-proxy/24-buffered_spec.lua
index c95cd7266784..15e639c0bb53 100644
--- a/spec/02-integration/05-proxy/24-buffered_spec.lua
+++ b/spec/02-integration/05-proxy/24-buffered_spec.lua
@@ -1,6 +1,6 @@
 local helpers = require "spec.helpers"
 local cjson   = require "cjson"
-
+local http_mock = require "spec.helpers.http_mock"
 
 local md5 = ngx.md5
 local TCP_PORT = helpers.get_available_port()
@@ -255,8 +255,8 @@ for _, strategy in helpers.each_strategy() do
       -- to produce an nginx output filter error and status code 412
       -- the response has to go through kong_error_handler (via error_page)
       it("remains healthy when if-match header is used with buffering", function()
-        local thread = helpers.tcp_server(TCP_PORT)
-
+        local mock = http_mock.new(TCP_PORT)
+        mock:start()
         local res = assert(proxy_client:send {
           method  = "GET",
           path    = "/0",
@@ -265,9 +265,9 @@ for _, strategy in helpers.each_strategy() do
           }
         })
 
-        thread:join()
         assert.response(res).has_status(412)
         assert.logfile().has.no.line("exited on signal 11")
+        mock:stop(true)
       end)
     end)
   end)
diff --git a/t/04-patch/03-fix-ngx-send-header-filter-finalize-ctx.t b/t/04-patch/03-fix-ngx-send-header-filter-finalize-ctx.t
new file mode 100644
index 000000000000..a4cc5c1644c0
--- /dev/null
+++ b/t/04-patch/03-fix-ngx-send-header-filter-finalize-ctx.t
@@ -0,0 +1,39 @@
+# vim:set ft= ts=4 sw=4 et fdm=marker:
+
+use Test::Nginx::Socket::Lua;
+
+#worker_connections(1014);
+#master_on();
+#workers(2);
+#log_level('warn');
+
+repeat_each(2);
+#repeat_each(1);
+
+plan tests => repeat_each() * (blocks() * 2);
+
+#no_diff();
+#no_long_string();
+run_tests();
+
+__DATA__
+
+=== TEST 1: send_header trigger filter finalize does not clear the ctx
+--- config
+    location /lua {
+        content_by_lua_block {
+            ngx.header["Last-Modified"] = ngx.http_time(ngx.time())
+            ngx.send_headers()
+            local phase = ngx.get_phase()
+        }
+        header_filter_by_lua_block {
+            ngx.header["X-Hello-World"] = "Hello World"
+        }
+    }
+--- request
+GET /lua
+--- more_headers
+If-Unmodified-Since: Wed, 01 Jan 2020 07:28:00 GMT
+--- error_code: 412
+--- no_error_log
+unknown phase: 0